BS 5628-1:2005 pdf download.Code of practice for the use of masonry— Part 1: Structural use of unreinforced masonry.
14 Masonry mortars14.1 General
The use of mortars should be in accordance with the recommendations given in BS 5628-3.For site mademortars, the mixing of the mortar should be in accordance with BS 5628-3.For factory made, semi-finishedfactory made and pre-batched masonry mortars, BS EN 998-2 applies.
Mortars should be designed or prescribed.For designed mortars, the compressive strength of the mortarprovides the control of the hardened mortar quality. When samples are taken from a designed mortar inaccordance with BS EN 1015-2,and tested in accordance with BS EN 1015-11, the compressive strength ofthe mortar should not be less than the declared compressive strength. Table 1 shows the relationship ofcompressive strength classes to strength.
14.2 Semi-finished factory made and pre-batched mortars
Semi-finished factory made and pre-batched mortars should conform to the requirements of BS EN 998-2.For designed mortars, the manufacturer should declare the strength that he is offering; for prescribedmortars,the provisions given in 14.1 apply.
Where pre-mixed lime-sand mortars are used, the specified addition of cement on site should be gauged.14.3 Colouring agents
Pigments should conform to the requirements of BS EN 12878 and should not exceed 10 % by mass of thecement in the mortar. Care should be taken to ensure that the pigment is evenly distributed throughoutthe mortar and that the strength of the mortar remains adequate.Carbon black should be limited to 3 %by mass of the cement.
14.4 Plasticizers
Plasticizers should conform to the requirements of BS EN 934-3.
If plasticizers are used, it is important to ensure that the manufacturer's instructions about quantity andmixing time are carefully followed.
14.5 Frost inhibitors
The use of calcium chloride or frost inhibitors based on calcium chloride is not permitted in mortars.
